This invention is directed generally to photoconductive imaging members with electron transporting polysilylenes. More specifically, in one embodiment the present invention is directed to negatively charged imaging members comprised of a photogenerating layer of hydrogenated, or halogenated amorphous silicon, an electron transport layer comprised of the polysilylenes as illustrated in U.S. Pat. No. 4,618,551, the disclosure of which is totally incorporated herein by reference, and situated therebetween a metal oxide layer. The aforementioned members in one particular aspect of the present invention are comprised of a supporting substrate, a hydrogenated amorphous silicon photogenerating layer, an electron transport layer comprised of a polysilylene, especially poly(methylphenyl) silylene, poly(n-propylmethyl) silylene, and other similar silylenes; and situated between the electron transport and photogenerating layers a metal oxide layer comprised of silicon oxides. The photoconductive imaging members of the present invention are particularly useful in electrophotographic, and especially xerographic imaging processes including those wherein there are selected for development liquid ink compositions. Further, the imaging members of the present invention possess chemical and electrical stability, and can be utilized for extended time periods in electrophotographic imaging apparatuses.
Imaging members comprised of polysilylenes are illustrated in U.S. Pat. No. 4,618,551, the disclosure of which is totally incorporated herein by reference. More specifically, there is illustrated in this patent a polysilylene hole transporting compound for use in layered imaging members comprised of the formula as recited in claim 1. More specifically, there is described in the aforementioned patent an improved layered photoresponsive imaging member comprised of a supporting substrate, a photogenerating layer, and as a hole transport layer in contact therewith, a polysilylene compound of the formula ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, and R.sub.6 are independently selected from the group consisting of alkyl, substituted alkyl, substituted aryl, and alkoxy; and m, n, and p are numbers that reflect the percentage of the particular monomer unit in the total polymer compound. Preferred polysilylene hole transporting compounds illustrated in this patent include poly(methylphenyl silylenes), which silylenes preferably have a weight average molecular weight of in excess of 50,000, and preferably are of a weight average molecular weight of about 75,000 to about 1,000,000. The aforementioned polysilylenes can be prepared by known methods, reference the Journal of Organometallic Chemistry, page 198, C27 (1980), R. E. Trujillo, the disclosure of which is totally incorporated herein by reference. Also, other polysilylenes can be prepared as described in the Journal of Polymer Science, Polymer Chemistry Edition, Vol. 22, pages 225 to 238, (1984), John Wiley and Sons, Inc., the disclosure of which is totally incorporated herein by reference. More specifically, the aforementioned polysilylenes can be prepared as disclosed in the aforesaid article by the condensation of a dichloromethylphenyl silane with an alkali metal such as sodium. In one preparation sequence, there is reacted a dichloromethyl phenyl silane in an amount of from about 0.1 mole with sodium metal in the presence of 200 milliliters of solvent, which reaction is accomplished at a temperature of from about 100.degree. C. to about 140.degree. C. There results, as identified by elemental analysis, infrared spectroscopy, UV spectroscopy, and nuclear magnetic resonance, the polysilylene products subsequent to the separation thereof from the reaction mixture.
In column 8, lines 57 to 68, of the U.S. Pat. No. 4,618,551 patent there is disclosed the selection of a photogenerator of hydrogenated amorphous silicon for incorporation into a photoconductive imaging member containing the aforementioned polysilylenes as a hole transport layer.
Other patents primarily of background interest are U.S. Pat. Nos. 4,518,670; 4,544,729; and 4,587,205; and U.K. No. 2,021,545.